Dyeing and chemical modification of keratins



United States Patent Offiee 2,933,365 Patented Apr. 19, 1960 DYEING ANDCHEMICAL MODIFICATION OF KERATINS Joseph E. Moore, Pinole, Califi,assignor to the United States of America as represented by the Secretaryof Agriculture No Drawing. Application November 20, 1957 Serial No.697,750

23 Claims. (Ci. 8-127.6) (Granted under Title 35, US. Code (1952 sec.266) A non-exclusive, irrevocable, royalty-free license in the inventionherein described, throughout the world for all purposes of the UnitedStates Government, with the power to grant sub-licenses for suchpurposes, is hereby granted to the Government of the United States ofAmerica.

This invention relates to the chemical modification of keratinmaterials, particularly wool in the form of fibers, threads, yarns,fabrics, or wool waste. The invention is also applicable to other typesof keratinous materials, as for example, various types of animal hairsuch as camel hair, mohair, horsehair, cattle hair, hog bristle,detached human hair and additional keratinous materials such as fur andsynthetic keratin fibers made from chicken feathers, animal hoof, horn,or other native keratin materials.

More particularly this invention concerns the dyeing :of keratinousmaterials by a treatment wherein normal disulphide linkages in thekeratin are replaced by different and novel linkages derived'fromchromophoric unsaturated amides, imides, or related compounds. Theinvention is concerned not only with the processes whereby such chemicalalterations are produced but also with the novel modified keratinsproduced by such chemical action. Further objects, features, andadvantages of the invention will be evident from the description herein.

It is well known that keratins are particularly characterized among theproteins as containing considerable amounts of chemically combinedsulphur. This sulphur is present in the protein molecule in a form knownas disulphide (or cystine) linkages. Thus the keratin molecule containsamino acids joined through amide linkages to form long chain structuresknown as polypeptides. These polypeptide chains are in turn connectedwith one another through disulphide linkages. The basic structure of akeratin may therefore be represented by the formula:

apart since the disulphide bonds which normally hold the polypeptidechains together are no longer present or at least the number of them isreduced.

It has been shown in the prior art that the properties of keratins,particularly wool, can be enhanced by the process of alkylation. In thisprocedure, the wool is treated with a reducing agent to disrupt thedisulphide bonds thus converting the SS-- bond into two thiol (-SH)bonds, one attached to each polypeptide chain. The wool is then reactedwith an alkylating agent such as 1,2-dibromoethane whereby thepolypeptide chains are It has also been shown that the reduction andalkylation can be performed essentially simultaneously by applying asolution containing both a reducing agent and an 5 alkylating agent tothe wool.

It has now been found that novel results are attained when the reducedkeratin is reacted with agents of an entirely different character thanthose used before. The agents in accordance with the invention containchromophore groups hence their reaction with the reduced keratin causesa dyeing of the keratin material. Since this dyeing or pigmentation ofthe material involves a chemical combination, the color is fast andresists removal by washing and other agencies deleterious toconventional dyeings. Also, by proper selection of the agent a dyeingeffect plus a cross-linking eifect can be attained. In such case theproperties of the keratin material are improved as regards resistance toalkalis, acids, reducing agents,

oxidizing agents, etc. Moreover, this improvement in 21,) quality is inaddition to the dyeing effect attained.

The agents of the invention are described as compounds containing anacyl-nitrogen group linked through the nitrogen to an aromatic group,the acyl radical containing an olefinic double bond between two carbonatoms, at least one of these carbon atoms being directly linked to thenon-0x0 carbonyl group of said acyl-nitrogen group, and wherein thearomatic group contains at least one chromophore group.

It is evident that in the agents containing'only one olefinic doublebond, only the dyeing efiect is obtained, whereas with the agentscontaining a plurality of olefinic double bonds, both dyeing and.cross-linking of polypeptide chains are obtained. This distinction isillustrated by the following equation:

5 (a) Reaction of reduced keratin with agent containing single olefinicbond:

X-SH

0Hoo ll CH-CO i X-S-CHOO GHQ-c0 (17) Reaction of reduced keratin withagent containing two olefinic bonds:

2X-SH CHCO\ /.OOOH NAr-N a )I ll Cir-o0 oo-orr XscHo o\ CO-OHSX 3 N-Ar-Norb-co (JO-CH:

In the above equations, X represents the polypeptide chain of theprotein molecule, R represents a monovalent 6 aromatic radicalcontaining a chromophore group, Ar represents a divalent aromaticradical containing a chromophore group. As illustrated in the aboveequations, the agents of the invention react by addition of the thiolgroups of the reduced protein to the activated unsaturated group of theamide or imide. The unsaturated group is activated by the presence of acarbonyl group adjacent to the carbon atom which bears the olefiniclinkage.

aasasos 3 Compounds having two carbonyl groups adjacent to theunsaturated linkage, e.g., derivatives of maleic acid, citraconic acid,itaconic acid, ethylmaleic acid, alpha methyl itaconic acid, etc., areespecially reactive because the double bond is activated to a greaterdegree.

In some instances, the reaction may additionally occur through reactionof free amino groups, hydroxyl groups, or amide groups in the proteinmolecule with the activated unsaturated radical of the agent, suchreactions involving the amino groups of the protein, are illustrated bythe following equations:

II CHI- (JO-CH.

X-NH'CHOO\ COCE-NH-X N-Ar-N Ha-CO (JO-CH:

In the above equations, X represents the polypeptide chain of theprotein, R represents a monovalent aromatic .radical containing achromophoric group and Ar represents a divalent aromatic radicalcontaining a chromophoric group.

By cross-linking the peptide chains of keratin fibers with the agentscontaining a plurality of activated olefinic unsaturated linkages, thereare produced chemically modified fibers which, in addition to the dyeingelfect attained, have marked advantages over the natural or originalfiber. Thus the modified fiber has an increased resistance to shrinkingand felting when subjected to laundering or other procedures wherein thefiber is contacted with aqueous, especially aqueous-alkaline, fluids.The modified fiber is also increased in resistance to biologicaldegradation as by bacteria, molds, enzymes and insect secretions.

The modified fiber has increased stabilitytoward other potentiallydeleterious agencies, as for example sunlight, ultra-violet light,reagents such as alkalis, acids, reducing agents, and oxidizing agents.

Many different classes of compounds may be employed as thekeratin-modifying agent within the purview of the invention.Representative examples of agents are given below by way of illustrationand not limitation.

A. Imides of maleic acid:

These compounds may be represented by the formula rality of chromophoregroups. Additionally the aromatic radical may contain auxochrome groups.Presence of the latter is particularly preferred where the chromophoregroup is not of itself sufficiently active to provide the desired depthof color. Typical of the chromophore groups which may be present are:azo-N=N; thic- '--NR -NHR', -NH (R being a lower alkyl group such asmethyl, ethyl, 'propyl, butyl, etc.); hydroxy-OH; alkoxy-OR'- (R' beingas above). 7

Additionally, the aromatic radical may contain substituents to impartwater-solubility to the agent, hence to facilitate reaction of the agentwith the reduced keratin in aqueous system. For such purpose there maybe one or more carboxyl or sulphonate groups, the latter beingpreferred.

Taking into consideration the above factors, typical values of R in theabove formula are:

COOH

some B. Imides of citraconic acid:

c H3CG o NR (HI-C6 where R has the meaning as above described.

C. Imides of itaconic acid:

orn oo -K 51 69 CH2 wherein R has the meaning as above described.

D. Imides of ethyl maleic acid:

wherein R has the meaning as above described.

E. Imides of alpha methyl itaconic acid:

cHacH-0o N-R ("ZIP-CO CH2 where R has the meaning as'above described.

F. Amides of acrylic acid: w H

CH =CHCO-NHR wherein R has the meaning as above described.

G. Amides of methacrylic acid:

OH2- (3-CONHR CH3 wherein R has the meaning as above described.

H. Amides of crotonic acidz" CH -CH=CI ICONH-R wherein R has the meaningas above described.

I. Amides of angelic acid:

0 na-oneo o O-NHR CHE" wherein R has the meaning as above=described J.Carbamide derivatives:

i R -NHCNHR .In the above formulas, R has themeaning as above described,R represents the acylradical of a monocarboxylic acid such as acrylic,methacrylic, crotonic, angelic, etc.; R represents the acyl radical of adibasic acid such as maleic, itaconic, citraconic, ethylmaleic,alphamethylitaconic, etc.

K. Derivatives of heterocyclic compounds, such as:

In the above formulas, R and R have the same significance as in categoryI; R has the meaning as above described.

A. Diimides of mal'eic acid:

C H-0 0 G 0-05: \N-AI--N/ 0 11-06 o OCH In the above formula Arrepresents a divalent aromatic radical which contains a chromophoregroup. To intensify the dyeing effect, the aromatic radical may containa plurality of chromophore groups. Additionally,

the aromatic radical may contain auxochrome groups. Presence of thelatter is particularly preferred Where the chromophore group is not ofitself sufficiently active to provide the desired depth of color.Typical of the chromophore groups which may be present are: azo- N=N-;thiocarbonyl-CS; nitroso-NO; azoXy-N ==NO--; nitro-NO azomethine-CH=N;carbonyl- CO--; ethenyl-&C;

Typical of the auxochrorne groups are: amino "groups NR' NHR, and NH (R'being a lower alkyl group such as methyl, ethyl, propyl, butyl, etc);hy-

droxy-OH; alkoxy-OR (R being as above).

Additionally, the aromatic radical may contain substituents to impartwater-solubility to the agent, hence to facilitate reaction, of theagent with the reduced keratin in aqueous systems. For such purpose,there may be one or more carboxy or sulphonategroups, the latter beingpreferred.

Taking into account these factors, typical values of AI in the aboveformula are:

SOaNa N (CHI)! KIZIW N O zNa S OaNe SOaNa SOaNa B. Diimides ofcitraconic acid:

CH;C-O CO-G-CH; N-Ar- 11-00 00-- H wherein Ar has the meaning as abovedescribed.

0'. Diimides of itaconic acid:

CHr-C 0 c 0-4113, N.A.r-'-N -00 0o- CH: iin,

wherein Ar has the meaning above described.

D'. Diimides of elghyl maleic acid:

wherein Ar has the meaning as above described.

8 E. Diimides of alpha-methyl itaconic acid: CfiPH-CO co-on-cn.

N-Ar-N CH: CH:

wherein Ar has the meaning as above described.

F. Diamides of acrylic acid:

wherein Ar has the, meaning as above'described.

G. Diamides of methacrylic acid:

1 1 'T n. a 011.

wherein R has the meaning as above described (in cate- W 40 K.Derivatives of heterocychc compounds, such ascar-{fro CH: 7 C CH:

NH-R

In the above formulas, R has the meaning as above described; Rrepresents the acyl radical of a monocarboxylic unsaturated acid as forexample acrylic acid,

methacrylic acid, crotcnic acid, angelic acid, ctc.; R up resents theacyl radical of a dibasic unsaturated acid such as maleic, itaconic,citraconic, ethyl maleic, alpha methyl itaconic, etc. I

L. The invention is not restricted to the use of crosslinking reagentscontaining two amide (or imide) radicals but the invention contemplatesthe use of cross-linking agents wherein there are more than twounsaturated amide or imide radicals. Representative compounds containingthree such radicals are depicted below, where- M. The cross-linkingagents need not necessarily be of symmetrical configuration and theinvention contemplates the use of compounds containing two or morediiferent unsaturated acyl radicals, as for example, compounds of thefollowing types wherein Ar has the meaning as above defined:

The keratin-modifying agents of the invention may be prepared byapplying conventional methods for producing amides or imides to aromaticamines containing chromophore groups. Thus, for example, the amines maybe reacted with the unsaturated carboxylic acids, preferably underconditions to eliminate the water of reaction. This can be done forexample by refluxing the reaction mixture and continuously separatingwater from the refluxing liquid. Instead of the acids themselves, theira=nhydrides or chlorides or bromides may be employed. Where unsaturateddicarboxylic acids or their derivatives are used, the reaction can becarried to the point of obtaining amides or by further dehydration aswith the aid of acetic anhydride or other convcntional dehydratingagent, the imides may be prepared.

The treatment of the wool or other ker-atinous material to replacedisulphide bonds by the novel amide or imide linkages is preferablycarried out in what may be termed a two-step process. This procedureinvolves two separate phases as follows: First, the keratin istreatedwith a reducing agent in known manner to split the disulphide bonds intothiol radicals or other radicals which behave in subsequent reactionsimilar to thiol radicals. The reduced keratin is then reacted with anyone of the agents as described herein.

Regarding the two-step process briefly noted above, the keratin is firstreacted with a reducing agent. As this agent one may use varioussulphur-containing, reductive di-" sulphidesplitting agents such assodium sulphide, sodium sulphite, sodium bisulphite, other water-solublesalts of -sulphurous or hydrosulphuric acid, formamidine sulphinic acid,sodium or zinc aldehyde sulphoxylates, sodium f .dithionates, orpreferably organic compounds containing thiol groups. Examples of thelatter are thioglycollic acid, sodium thioglycollate, beta-mercaptoethanol, 1,2- dithioglycerol, butyl mercaptan, and so forth. In generalthe reduction is carried out by immersing the keratin material in watercontaining an amount of the reducing agent in excess of thatstoichiometrically calculated to reduce the desired number of disulphidelinkages in the amount of keratin material used. Where the reducingagent has limited solubility in water, a wetting and dispersing agentsuch as a long chain alkyl benzene sulphonate or long chain alkylsulphate may be added to keep the reducing agent in suspension and topromote better contact between the keratin and the reducing agent. Suchconditions as temperature and time of reaction may be varied dependingon such factors as the type of keratin being treated, the eflicacy ofthe reducing agent selected, the degree of splitting of disulphidebonds, and so forth. In general the temperature may vary from about 20C. to about 150 'C. Where the keratin material is a fiber such as woolor fur or hair, it is preferred to limit the upper range of temperatureto about 60 C. thus to avoid degradation of polypeptide chains or otherundesirable side reactions. Where refractory keratins such as cattlehoof or horn are being treated, higher temperatures such as available inconducting the process under superatmospheric pressure, may be employedto obtain the desired reduction of disulphide bonds. The reaction isdiscontinued when the desired proportion of disulphide linkages havedisrupted. In general, the time of reaction may vary from 30 minutes to24 hours or more depending on the nature of the keratin material, thetemperature of reaction, the efiicacy of the reducing agent, theproportion of disulphide linkages to be broken, etc. The reduction mayinvolve splitting only a small proportion of the disulphide bonds, asfew as /z% for instance, or may be a more intensive reduction up to themaximum of reducing of the disulphide linkages. In general where onlythe dyeing effect is desired in the subsequent step, the reduction islimited to split about 0.5 to 5% of the disulphide groups, such amountof reduction not materially lowering the wet strength of the fiber.Where it is desired to get both dyeing and cross-linking effects in thesubsequent step, the degree of reduction is conducted so as topreferably split at least 25% of the disulphide bonds whereby to attaina high degree of stabilization in the cross-linking step. Althoughreduction of at least 25% of the disuphide bonds is preferred,substantial increases in stability will be obtained by cross-linking ofthe keratin material which has been reduced to lesser extents forexample as low as 5% disulphide bond splitting. It is evident that theconditions of the reduction, for example, the temperature, concentrationof reducing agent, time of reaction, etc. can be varied as required toattain the desired degree of disulphide bond splitting. The medium inthe reduction may contain an alkaline agent such as sodium hydroxide,potassium hydroxide, sodium carbonate, borax, or the like to promote thesplitting reaction. Where alkaline material is used the pH of the mediumshould be less than about pH 9 to avoid hydrolysis of polypeptidechains. Generally it is preferred to use slightly acid or neutralconditions (about pH 4- to 7) to avoid any possibility of polypeptidedegradation.

After the reduction step has been completed, the reduced keratin isthoroughly washed to remove all excess reducing agent. Agents such asorganic thiols if left in the keratin mass would react with themodifying agent in the next step. Solvents such as alcohol, acetone,benzene, etc. may be used as necessary to remove residual reducingagent.

The washed, reduced keratin is then immersed in a solution of the amide(or imide) agent in an amount to furnish one oleflnic linkage for eachthiol group in the reduced keratin. Usually, an excess of the agent isemployed to ensure complete reaction. Where the agent is agents arederived from monocarboxylic acids.

masses soluble in water, water may be used as the solvent there- 'for.In other cases it may be necessary to use an inert solvent in which theagent is soluble, for example, ethanol, propanol, isopropanol, butanol,benzene, dioxane, ether, petroleum ether, gasoline, acetone, hexane, ormonoethers of ethylene glycol such as the methyl, ethyl, isopropylethers. Where water is used as the medium, the agent may be dispersed inthe aqueous system by the use of a wetting and dispersing agent such asa long-chain alkyl benzene sulphonate, long chain alkyl sulphate, or thelike. The temperature of the reaction may be varied from to 100 C. Wherethe material being processed is a fiber such as wool, hair, fur, etc.,it is preferred to use a temperature not higher than about 60 C. wherebyto avoid degradation of the polypeptide chains. One of the features ofthe invention is that the addition of the thiol radical to the olefinicdouble bond takes place at practical rates even at room temperature sothat boiling as is necessary in conventional dyeing is not required. Thedyeing in accordance with the invention which may be performed at 20 to60 C. thus has the additional advantage that possibility of degradingthe protein molecule is eliminated. The time of reaction will varydepending on such factors as the temperature of reaction, the reactivityof the amide or imide used, and the degree of modification desired. Ingeneral, the reaction may take anywhere from minutes to 24 hours ormore. As noted previously, agents which are derived from dicarboxylicacids such as maleic and itaconic contain doubly activated olefiniclinkages and with such agents the addition of thiol groups will proceedmore rapidly than where the In any event, the course of the reaction canbe followed by examining the color of the keratin from time to time and.

discontinuing the reaction when the desired depth of color is produced.Where polyamides or polyimides are used, the course of the reaction canalso befollowed by conducting tensile strength or similar physical testson the fiber from time to time since establishment of the cross linksbetween polypeptide chains will result in increasing the wet strength'ofthe keratin material being processed. After the reaction is completed,the modified keratin material is washed free of excess reagents anddried.

It is generally preferred to conduct the reaction of the reduced keratinwith the amide (or imide) reagent under mildly alkaline conditions ofpH, for example at a pH of about 7.5 to 9. Such conditions can beattained by addition of suitable alkaline materials or buffers such assodium carbonate, borax, trisodium phosphate, potassium carbonate, etc.The same effect can be attained by treating the reduced keratin materialwith. a solution of alkaline material before it is contacted with theamide (or imide) reagent. This latter :mode of procedure is preferredwhere the modifying agent is insoluble in water and is applied to thekeratin dissolved in an organic solvent.

The invention is further demonstrated by the following examples.

Example I CH-OO The yarn was allowed to remain in the solution overnightat room temperature. The yarn was then removed and washed. It wasobserved that the yarn was evenly dyed a yellow color. The'yarn waswashed in warm water containing 0.5% sodium oleate and it was observedthat the dye did not fade nor run.

Example 11 A solution of 10 g. of para phenylazo aniline in 100 ml.chloroform was poured slowly into a solution of 5 g. of maleic anhydridein 150 m1. of chloroform: while stirring. After agitating the mixturefor /2 hr. at room temperature the precipitate was filtered off, washedwith chloroform and recrystallized from dimethyl formamide. Thirteengrams of N-(paraphenylazophenyl) maleamic acid was obtained. Five gramsof this compound was mixed with 20 ml. acetic anhydride and 1 g. sodiumacetate. The mixture was heated on the water bath until solution wascomplete. The solution was cooled, poured onto ice and after the ice hadmelted the material was filtered. The material on the filter wasrecrystallized from ethanol to yield 3.5 grams of N(paraphenylazophenyl)maleimide.

Having thus described the invention, what is claimed 1s:

1. A method of dyeing and chemically modifying a keratinous materialwhich comprises reacting the keratinous material in a reduced state witha compound containing an acyl-nitrogen group linked through the nitrogento an aromatic group, the acyl radical containing an olefinic doublebond between two carbon atoms one of which is directly linked to thenon-0x0 carbonyl group of said acyl-nitrogen group, and wherein thearomatic group contains a chromophore group selected from the classconsisting of azo, nitroso, azoxy, nitro, and azomethine.

2. A method of dyeing and chemically modifying wool which comprisesreacting wool in a reduced state with a compound containing anacyl-nitrogen group linked through the nitrogen to an aromatic group,the acyl radical containing an olefinic double bond between two carbonatoms one of which is directly linked to the non-0x0 carbonyl group ofsaid acyl-nitrogen group, and wherein the aromatic group contains achromophore group selected from the class consisting of azo, nitroso,azoxy, l nitro, and azomethine.

3. A method of dyeing and chemically modifying wool which comprisesreacting wool in a reduced state with a compound of the formulawherein Ris an aromatic'group containing a chromophore group selected from theclass consisting of azo, nitroso, azoxy, nitro, and azomethine, and R'is an aliphatic radical containing an olefinic double bond between I twocarbon atoms one of which is directly linked to one of the -CO--radicals.

4. A method of dyeing and chemically modifying wool which comprisesreacting wool in a reduced state with a compound of the formulawherein Ris an aromatic radical containing a chromophore group selected from theclass consisting of azo, nitroso, azoxy, nitro, and azomethine. V

5. The process of claim 4 wherein R is para-phenylazophenyl.

6. A method of dyeing and chemically modifying wool 13 which comprisesreacting wool in a reduced state with a compound of the formulawherein Rrepresents an aromatic radical containing a chromophore group selectedfrom the class consisting of azo, nitroso, azoxy, nitro, and azomethineand R and R" each represents a member of the group consisting ofhydrogen and lower alkyl.

7. The method of claim 6 wherein R and R" are each hydrogen.

8. A method of modifying wool to replace original disulphide bonds bystable cross-linkages and to simultaneously dye it which comprisesreacting the wool in a reduced state with a compound containing twoacylnitrogen groups connected through the nitrogens to an aromaticgroup, each acyl radical containing an olefinic linkage between twocarbon atoms one of which is directly linked to the non-oxo carbonylgroup of said acyl nitrogen group and wherein the aromatic groupcontains a chromophore group selected from the class con sisting of azo,nitroso, azoxy, nitro, and azomethine.

9. A method of modifying wool to replace original disulphide linkages bystable cross-linkages and to simultaneously dye it which comprisesreacting the wool in a reduced state with a compound of the formulawhereAr is an aromatic radical containing a chromophore group selected fromthe class consisting of azo, nitroso, azoxy, nitro, and azomethine, andR is an aliphatic radical containing an olefinic double bond between twocarbon atoms one of which is directly linked to one of the CO--radicals.

10. A method of modifying wool to replace original disulphide linkagesby stable cross-linkages and to simultaneously dye it which comprisesreacting the wool in a reduced state with a compound of theformulawherein Ar is an aromatical radical containing a chromophoregroup selected from the class consisting of azo, nitroso, azoxy, nitro,and azomethine.

11. A method of modifying wool to replace original disulphide linkageswith stable cross-linkages and to simultaneously dye it which comprisesreacting the wool in a reduced state with a compound of the formula-- SXi where X represents the portion of the keratin molecule to which thedisrupted disulphide linkage is attached, n is an integer from 1 to 4,and M represents a compound containing an acyl-nitrogen group attachedthrough the nitrogen to an aromatic group containing a chromophore groupselected from the class consisting of azo, nitroso,

azoxy, nitro, and azomethine. the acyl-nitrogen group originallycontaining an olefinic linkage between two carbon atoms one of thesecarbon atoms being directly linked to the non-0x0 carbonyl group of saidacyl-nitrogen group, and wherein in the chemically modified keratin theolefinic linkage is satisfied by addition of an -S-X and an --H radical.

14. A chemically modified wool in which disulphide linkages of the woolmolecule have been disrupted and converted to linkages of the typerepresented by- X-S NR H o6 where X represents the portion of the woolmolecule to which the disrupted disulphide linkage is attached, R is anaromatic radical containing a chromophore group selected from the classconsisting of azo, nitroso, azoxy, nitro, and azomethine, R is analiphatic radical originally containing an olefinic linkage between twocarbon atoms one of these carbon atoms being directly linked to one ofthe -CO radicals, and wherein in the chemical modified wool the olefinelinkage is satisfied by addition of the XS and H radicals thereto.

15. A chemically modified wool in which disulphide linkages of the woolmolecule have been disrupted and converted to linkages of the typerepresented bywherein X represents the portion of the wool molecule towhich the disrupted disulphide linkage is attached and R is an aromaticradical containing a chromophore group selected from the classconsisting of azo, nitroso, azoxy, nitro, and azomethine.

16. The product of claim 15 wherein R is paraphenylazophenyl.

17. A chemically modified wool in which disulphide linkages of the woolmolecules have been disrupted and converted to linkages of the typerepresented bywherein X represents the portion of the wool molecule towhich the disrupted disulphide linkage is attached, R is an aromaticradical containing a chromophore group selected from the classconsisting of azo, nitroso, azoxy, nitro, and azomethine, and R and Reach represents a member of the group consisting of hydrogen and loweralkyl.

18. The product of claim 17 wherein R and R" are each hydrogen.

19. The product of claim 17 wherein R and R are each hydrogen and R isparaphenylazophenyl.

20. A chemically modified wool in which disulphide linkages of the woolmolecule have been disrupted and converted to linkages of the typerepresented bywherein X represents the portion of the wool molecule towhich the disrupted disulphide linkages are attached, Ar is an aromaticradical containing a chromophore group selected from the classconsisting of azo, nitroso, azoxy, nitro, and azomethine, R is analiphatic radical originally containing an olefinic linkage between twocarbon atoms one of these carbon atoms being directly linked to one ofthe --CO radicals, and wherein in the chemically modified wool theolefinic linkage is satisfied by addition of the X-S and H radicalsthereto.

21. A chemically modified wool in which disulphide 15 linkages of thewool molecule have been disrupted and converted to linkages of the typerepresented by X-SCHC0 COCHSX NArN CH2C6 CO--CH2 wherein X representsthe portion of the wool molecule to which the disrupted disulphidelinkage is attached and Ar is an aromatic radical containing achromophore group selected from the class consisting of azo, nitroso,azoxy, nitro, and azomethine.

22. A chemically modified wool in which disulphide linkages of the woolmolecule have been disrupted and converted to linkages of the typerepresented bywherein X represents the portion of the wool molecule towhich the disrupted disulphide linkage is attached. Ar is an aromaticradical containing a chromophore group selected from the classconsisting of azo, nitroso, azoxy, nitro, and azomethine, and R and R"each represents a member of the group consisting of hydrogen and loweralkyl.

23. The product of claim 22 wherein R and R" are each hydrogen.

References Cited in the file of this patent UNITED STATES PATENTSHaefele Oct. 28, 1952 -2,615,783 Haefele Oct. 28, 1952 2,804,455 Dorlarset a1. Aug. 27, 1957 Moore et a1. Sept. 2, 1958

1. A METHOD OF DYEING AND CHEMICALLY MODIFYING A KERATINOUS MATERIALWHICH COMPRISES REACTING AND KERATINOUS MATERIAL IN A REDUCED STATE WITHA COMPOUND CONTAINING AN ACYL-NITROGEN GROUP LINKED THROUGH THE NITROGENTO AN AROMATIC GROUP, THE ACYL RADICAL CONTAINING AN OLEFIN DOUBLE BONDBETWEEN TWO CARBON ATOMS ONE OF WHICH IS DIRECTLY LINKED TO THE NON-OXOCARBONYL GROUP OF SAID ACYL-NITROGEN GROUP, AND WHEREIN THE AROMATICGROUP CONTAINS A CHROMOPHORE GROUP SELECED FROM THE CLASS CONSISTING OFAZO, NITROSO, AZOXY, NITRO, AND AZOMETHINE.